Recently, light based scanning photomedical systems have been developed to accurately and efficiently treat tissue by automatically generating and applying patterns of light onto target tissue. For example, U.S. patent application publications 2005/0286019 and 2007/0147730 describe ophthalmic light beam pattern scanning devices that safely and efficiently scan a light beam in a predetermined pattern onto target tissue (e.g. in the patient's eye). The system allows the physician to align the light pattern to the target tissue, where the system automatically scans the light pattern onto the target tissue based upon a single activation by the physician. The application of light beam treatment using such a system can be accomplished far more quickly and accurately compared to earlier light beam systems that only allowed the physician to apply the light beam spots manually one at a time.
In such scanning photomedical systems, the light beam source is designed as an integral part of the scanning delivery system for several reasons. First, the control electronics for the system must have complete control over the operation of the light source in order to monitor and adjust the beam power, the beam activation, the beam wavelength, etc. Second, the optical elements used to receive, scan and deliver the light beam to the target tissue were designed integrally with the light source such that the desired spot size and pattern configuration could be achieved given the characteristics of the light beam (such as diameter, divergence, wavelength, etc.). Because these scanning systems are used for sensitive medical procedures such as ophthalmic photocoagulation, safety and reliability concerns and regulations dictate that the system have full control over the light source to ensure that the dosages and the locations of the light patterns are delivered safely and reliably.
It has recently become desirable to implement light-based scanning photomedical systems which utilize light sources external to the system, with little or no system control over the external light source. This would allow manufacturers of such photomedical systems to multi-source the suppliers of light sources. It would also provide users the ability to use existing light sources and/or swap light sources, for lower cost and greater flexibility. However, using light sources external to the photomedical system, with little or no control over the light source, compromises the integrity and reliability of existing scanning photomedical systems. There is a need for a scanning photomedical system that safely and reliably scans light beams onto the target tissue, where there is little or no control over the treatment light source by the photomedical system.